Hyundai Motor's mid-sized Sonata sedan looks set to become South Korea's best selling car for the second consecutive year.

Although the vehicle had lagged behind the compact Avante until August, Sonata sales picked up massively following the launch of the sixth generation last month.

According to industry data, the gap between the Sonata and the Avante was 4,894 units in favour of the larger vehicle at the end of last month, the Korea Herald reported.

Orders are already held for over 60,000 units of the latest version and the remaining three months of the year will see about 17,000 units sold, pushing up the tally for the year to around 140,000 units.